Last November, the Australian actor said of his Batman character – a sardonic sociopath: "It's the most fun I've had with a character and probably will ever have. The movie itself is far exceeding my expectations. I think it's going to be a really fun movie to watch."

Unfortunately, of course, Ledger would never be afforded that opportunity. The Australian actor, 28, was found dead from an accidental prescription-drug overdose in his Manhattan apartment on Jan. 22.

With the film now being previewed, Nolan says of Ledger's role, "The psychopathic clown, that's an icon to stand with the guy with the ears and cape. It's just a wonderful visual relationship, and it's a terrifying image."

Christian Bale's Reaction

For his part, Bale, 34, admitted to watching the preview Thursday with a heavy heart, but said of his costar's performance, "I hope that this can be seen as a celebration of his work."

Ledger, said the Welsh actor, "did a phenomenal job. It was a real joy working with the man. It was a joy knowing him, as well. I liked him a great deal, and I liked also how seriously he took his work."